Abstract

The enthalpy,
entropy, and exergy flows resulting from the real gas effects of
in ideal pulse tube cryocoolers are described. The discussion follows a previous description of the real gas effects of
in ideal pulse tube cryocoolers and makes use of a recently developed model of the thermophysical properties of
This model is used to describe how the thermodynamic flows are affected by real gas phenomena of
and compares these effects to similar effects for

The analysis was done over the pressure range 0.3–2 MPa and temperatures down to 1 K. At 2 MPa there is almost no difference in the cooling power between
and
At lower pressures, using
is advantageous. There is a 1–2 K reduction in the
cooling power vs. temperature curves compared to those for
in the 0.3–1 MPa range.